I can reproduce on the latest patched build, but this is specific for
the 64bit version of R. On a 32bit it works as expected:
> big <- 1.797693134862315708385e+308
> sqrt(big)
[1] 1.340781e+154
> big^0.5
[1] 1.340781e+154
The 64bit part might have something to do with it, and now move out of
the way for people that actually know what they're talking about...
Cheers
Joris
On Mon, Nov 21, 2011 at 3:41 PM, Martyn Byng <martyn.b...@nag.co.uk> wrote:
> Hi,
>
> I'm getting some strange behaviour when trying to use the power operator
> (a^b) when a is large and b is less than one:
>
> big <- .Machine$double.xmax
> big
> big^0.5
> sqrt(big)
>
>> big <- 1.797693134862315708384e+308
>> big^0.5
> [1] Inf
>> sqrt(big)
> [1] 1.340781e+154
>
>
> I'm guessing that this behaviour is not expected, or am I missing
> something about ^?
>
> Cheers
>
> Martyn
>
>
>
>> sessionInfo()
> R version 2.14.0 (2011-10-31)
> Platform: x86_64-pc-mingw32/x64 (64-bit)
>
> locale:
> [1] LC_COLLATE=English_United Kingdom.1252
> [2] LC_CTYPE=English_United Kingdom.1252
> [3] LC_MONETARY=English_United Kingdom.1252
> [4] LC_NUMERIC=C
> [5] LC_TIME=English_United Kingdom.1252
>
> attached base packages:
> [1] stats graphics grDevices utils datasets methods base
>
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--
Joris Meys
Statistical consultant
Ghent University
Faculty of Bioscience Engineering
Department of Mathematical Modelling, Statistics and Bio-Informatics
tel : +32 9 264 59 87
joris.m...@ugent.be
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